Titanium (Ti) thin films were created on glass and Pb(Zr, Ti)O3 (PZT) substrates using magnetic RF sputtering apparatus. Nano-indentation tests were carried out to study the influence of the Ti thin layer on piezoelectric properties. The piezoelectric properties of the PZT plate and a Ti sputtered one were also measured by laser Doppler vibrometer. Furthermore, some characteristics, such as crystalline structure, depth profiles, and surface roughness of the films were observed by means of an atomic force microscope (AFM). Main conclusions obtained in this study are summarized as follows: (1) From detailed observation and analytical results of AFM, the surface roughness, Ra, tends to increase as Ti film thickness increases. (2) Some of the mechanical properties, such as reduced modulus Er and hardness H obtained from nano-indentation tests, are significantly related to film thickness. (3) The validity of piezoelectric finite element analysis (ANASYS program) for deformation of a piezoelectric material was investigated. As a result, piezoelectric response properties are present in as-received PZT specimens and Ti-sputtered PZT specimens. Experimental and FE analytical results indicate that the piezoelectric coefficient is significantly influenced by Ti layer.
{"title":"Processing and Functional Evaluation of Titanium Thin Films for Biomimetic Micro Actuator","authors":"T. Sakai, Sodai Hoshiai, E. Nakamachi","doi":"10.1299/JSMEA.48.451","DOIUrl":"https://doi.org/10.1299/JSMEA.48.451","url":null,"abstract":"Titanium (Ti) thin films were created on glass and Pb(Zr, Ti)O3 (PZT) substrates using magnetic RF sputtering apparatus. Nano-indentation tests were carried out to study the influence of the Ti thin layer on piezoelectric properties. The piezoelectric properties of the PZT plate and a Ti sputtered one were also measured by laser Doppler vibrometer. Furthermore, some characteristics, such as crystalline structure, depth profiles, and surface roughness of the films were observed by means of an atomic force microscope (AFM). Main conclusions obtained in this study are summarized as follows: (1) From detailed observation and analytical results of AFM, the surface roughness, Ra, tends to increase as Ti film thickness increases. (2) Some of the mechanical properties, such as reduced modulus Er and hardness H obtained from nano-indentation tests, are significantly related to film thickness. (3) The validity of piezoelectric finite element analysis (ANASYS program) for deformation of a piezoelectric material was investigated. As a result, piezoelectric response properties are present in as-received PZT specimens and Ti-sputtered PZT specimens. Experimental and FE analytical results indicate that the piezoelectric coefficient is significantly influenced by Ti layer.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124386163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In Japan, lightning damage to FRP blades for wind power generators is increasing, together with the increase in wind power generator installation in recent years. Lightning damage is a big issue in Japan since lightning in Japan seems to be severer than in Europe and the US. In Kochi, Shikoku, Japan, six 600-750kW grade generators have been installed, and some of them have been damaged by lightning several times. In order to solve this issue, the Kochi University of Technology received a research request of lightning protection, sponsored by the Kochi prefecture in 2002. After surveying the literature and questioning related organizations such as NREL (National Renewable Energy Laboratories) and Toray USA, experiments to reproduce lightning damage to FRP specimens were planned. The specimens prepared for this research are 1/2 size models and a 2/4 part of the full size blade. In the previous experiment, flat plate specimens of 450mm width × 2.5m length × 4mm thickness were used, and the experiments produced the damage by lightning. However, the damages were not exactly the same as the ones in the actual field. Therefore, this experiment aims to reproduce the blade failure in the actual field and to clarify the failure mechanism, using the 1/2 size blade model and full size blade specimens. The experiments were conducted mainly in the Toshiba Hamakawasaki High Voltage High Power Testing Laboratory as was made in the previous experiments. This Testing Laboratory is one of the biggest test laboratory for experiments involving high electric voltage and large current. The results showed the reproduction of the failed blades in fields, and clarified the failure mechanism.
{"title":"Reproduction of FRP Blade Failure for Wind Power Generators by Lightning and its Mechanism","authors":"H. Sakamoto, M. Hanai","doi":"10.1299/JSMEA.48.465","DOIUrl":"https://doi.org/10.1299/JSMEA.48.465","url":null,"abstract":"In Japan, lightning damage to FRP blades for wind power generators is increasing, together with the increase in wind power generator installation in recent years. Lightning damage is a big issue in Japan since lightning in Japan seems to be severer than in Europe and the US. In Kochi, Shikoku, Japan, six 600-750kW grade generators have been installed, and some of them have been damaged by lightning several times. In order to solve this issue, the Kochi University of Technology received a research request of lightning protection, sponsored by the Kochi prefecture in 2002. After surveying the literature and questioning related organizations such as NREL (National Renewable Energy Laboratories) and Toray USA, experiments to reproduce lightning damage to FRP specimens were planned. The specimens prepared for this research are 1/2 size models and a 2/4 part of the full size blade. In the previous experiment, flat plate specimens of 450mm width × 2.5m length × 4mm thickness were used, and the experiments produced the damage by lightning. However, the damages were not exactly the same as the ones in the actual field. Therefore, this experiment aims to reproduce the blade failure in the actual field and to clarify the failure mechanism, using the 1/2 size blade model and full size blade specimens. The experiments were conducted mainly in the Toshiba Hamakawasaki High Voltage High Power Testing Laboratory as was made in the previous experiments. This Testing Laboratory is one of the biggest test laboratory for experiments involving high electric voltage and large current. The results showed the reproduction of the failed blades in fields, and clarified the failure mechanism.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"67 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120897156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Most of magnesium alloy products are manufactured by die casting or thixo-molding processes. However, there is extremely little use of the products by metal forming due to high resisting plastic deformation in normal temperature and their expensive cost. In this study, to make clear the plastic deformability, stress and strain behaviors of Mg alloy AZ31 hot rolled sheet in plane strain compression in the temperature from 20 ◦ C to 250 ◦ C have been discussed. Tension test and plane strain compression test have been performed to obtain the equivalent stress and equivalent plastic strain relations. The plane strain compression tests with some lubricants have been performed, and the e ff ect of friction between die and deforming material on plastic deformation behaviors has been investigated by the elastic-plastic finite element analysis. Optical microstructures of deformed materials are also observed.
{"title":"Stress and Strain Behaviors of Mg Alloy AZ31 in Plane Strain Compression","authors":"Ikuo Yarita, T. Naoi, T. Hashizume","doi":"10.1299/JSMEA.48.299","DOIUrl":"https://doi.org/10.1299/JSMEA.48.299","url":null,"abstract":"Most of magnesium alloy products are manufactured by die casting or thixo-molding processes. However, there is extremely little use of the products by metal forming due to high resisting plastic deformation in normal temperature and their expensive cost. In this study, to make clear the plastic deformability, stress and strain behaviors of Mg alloy AZ31 hot rolled sheet in plane strain compression in the temperature from 20 ◦ C to 250 ◦ C have been discussed. Tension test and plane strain compression test have been performed to obtain the equivalent stress and equivalent plastic strain relations. The plane strain compression tests with some lubricants have been performed, and the e ff ect of friction between die and deforming material on plastic deformation behaviors has been investigated by the elastic-plastic finite element analysis. Optical microstructures of deformed materials are also observed.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"190 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124217895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yohei Inagaki, A. Suzumura, T. Ikeshoji, T. Yamazaki
Braze Pressure Welding (BPW) with high frequency induction heating is a newly developed pressure welding technique using interlayer metals for welding the general steel pipes for pipe arrangement in buildings. BPW enables to make joints by solid-state welding in air with relatively small deformation. In this method, the interlayer metal is expected to play the primary role in making high performance joints. It removes contaminations from the joining surface of the base metal and forms fillets at the gaps around the joint. It had been revealed by some experiments and/or numerical analyses in previous research that the BPW joint had higher tensile strength than the brazed joint, and that the fillet can improve the joint strength. In this study, in order to investigate the cleaning effect of interlayer metal more closely, a low carbon steel plate specimen was brazed mainly by Ni-based brazing filler using a tungsten spacer. The microscopy and EPMA analysis on the joints made by various brazing temperatures and durations confirmed that the oxide films on the joining surfaces were removed and discharged from the joining region by the interlayer metal.
{"title":"Cleaning Effect of Interlayer Metal on the Joining Surface during Braze Pressure Welding","authors":"Yohei Inagaki, A. Suzumura, T. Ikeshoji, T. Yamazaki","doi":"10.1299/JSMEA.48.413","DOIUrl":"https://doi.org/10.1299/JSMEA.48.413","url":null,"abstract":"Braze Pressure Welding (BPW) with high frequency induction heating is a newly developed pressure welding technique using interlayer metals for welding the general steel pipes for pipe arrangement in buildings. BPW enables to make joints by solid-state welding in air with relatively small deformation. In this method, the interlayer metal is expected to play the primary role in making high performance joints. It removes contaminations from the joining surface of the base metal and forms fillets at the gaps around the joint. It had been revealed by some experiments and/or numerical analyses in previous research that the BPW joint had higher tensile strength than the brazed joint, and that the fillet can improve the joint strength. In this study, in order to investigate the cleaning effect of interlayer metal more closely, a low carbon steel plate specimen was brazed mainly by Ni-based brazing filler using a tungsten spacer. The microscopy and EPMA analysis on the joints made by various brazing temperatures and durations confirmed that the oxide films on the joining surfaces were removed and discharged from the joining region by the interlayer metal.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122554965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is known that the single-modal Weibull model describes well the size effect of brittle fiber tensile strength. However, some ceramic fibers have been reported that single-modal Weibull model provided biased estimation on the gauge length dependence. A hypothesis on the bias is that the density of critical defects is very small, thus, fracture probability of small gauge length samples distributes in discrete manner, which makes the Weibull parameters dependent on the gauge length. Tyranno ZMI Si-Zr-C-O fiber has been selected as an example fiber. The tensile tests have been done on several gauge lengths. The derived Weibull parameters have shown a dependence on the gauge length. Fracture surfaces were observed with SEM. Then we classified the fracture surfaces into the characteristic fracture patterns. Percentage of each fracture pattern was found dependent on the gauge length, too. This may be an important factor of the Weibull parameter dependence on the gauge length.
{"title":"Bias in the Weibull Strength Estimation of a SiC Fiber for the Small Gauge Length Case","authors":"T. Morimoto, S. Nakagawa, S. Ogihara","doi":"10.1299/JSMEA.48.194","DOIUrl":"https://doi.org/10.1299/JSMEA.48.194","url":null,"abstract":"It is known that the single-modal Weibull model describes well the size effect of brittle fiber tensile strength. However, some ceramic fibers have been reported that single-modal Weibull model provided biased estimation on the gauge length dependence. A hypothesis on the bias is that the density of critical defects is very small, thus, fracture probability of small gauge length samples distributes in discrete manner, which makes the Weibull parameters dependent on the gauge length. Tyranno ZMI Si-Zr-C-O fiber has been selected as an example fiber. The tensile tests have been done on several gauge lengths. The derived Weibull parameters have shown a dependence on the gauge length. Fracture surfaces were observed with SEM. Then we classified the fracture surfaces into the characteristic fracture patterns. Percentage of each fracture pattern was found dependent on the gauge length, too. This may be an important factor of the Weibull parameter dependence on the gauge length.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124949102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Ikeshoji, Y. Watanabe, A. Suzumura, T. Yamazaki
During the brazing process of the rocket engine’s nozzle skirt assembly made from Fe-Ni based super alloy pipes with Pd based brazing filler, the erosion corrosion pits were sometimes engraved on those pipes’ surface. The corrosion is considered to be assisted by the dynamic flow of the molten brazing filler. In order to estimate the amount of erosion corrosion and to prevent it, the solubility and the dissolution rate of Ni to the molten Ag-Cu-Pd brazing filler are measured experimentally. The Ni crucible poured with the Ag-Cu-Pd brazing filler was heated up to 1320K and quenched after the various keeping time. The microstructure of the solidified brazing filler part’s cross sections was observed, and the amount of the dissolved Ni was estimated using the image processing technique. The solubility was about 5.53mass%and the initial dissolution rate was 6.28 × 10-3mass%/s. Using these data, more elaborate dynamic flow simulation will be able to conduct.
{"title":"Solubility and Dissolution Rate of Ni Base Alloy to Molten Ag-Cu-Pd Brazing Filler","authors":"T. Ikeshoji, Y. Watanabe, A. Suzumura, T. Yamazaki","doi":"10.1299/JSMEA.48.346","DOIUrl":"https://doi.org/10.1299/JSMEA.48.346","url":null,"abstract":"During the brazing process of the rocket engine’s nozzle skirt assembly made from Fe-Ni based super alloy pipes with Pd based brazing filler, the erosion corrosion pits were sometimes engraved on those pipes’ surface. The corrosion is considered to be assisted by the dynamic flow of the molten brazing filler. In order to estimate the amount of erosion corrosion and to prevent it, the solubility and the dissolution rate of Ni to the molten Ag-Cu-Pd brazing filler are measured experimentally. The Ni crucible poured with the Ag-Cu-Pd brazing filler was heated up to 1320K and quenched after the various keeping time. The microstructure of the solidified brazing filler part’s cross sections was observed, and the amount of the dissolved Ni was estimated using the image processing technique. The solubility was about 5.53mass%and the initial dissolution rate was 6.28 × 10-3mass%/s. Using these data, more elaborate dynamic flow simulation will be able to conduct.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122470890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Current study presents one of effective techniques to improve mechanical properties of PLA (Poly-Lactic Acid)-based bamboo fiber composite. Commercially available Micro-Fibrillated Cellulose (MFC) obtained from wood pulp was applied as an enhancer to the composite. The bamboo fibers were extracted by steam explosion method and they were also rubbed in water to remove xylem (soft-wall cells). The liquid-based MFC, PLA and the bamboo fiber were mixed in water for several minutes and they were filtrated under vacuum pressure. To fabricate the composite, remained sheets were then hot pressed after dry. Three-point bending strength and Mode I fracture toughness of the composite were significantly improved, even when 10% of the MFC was added into the PLA/BF composite in weight. If small amount of MFC added into the bamboo fiber composite, tangled MFC fibers prevented the growth of micro crack along the interface between bamboo fiber and matrix.
{"title":"Improvement of Interfacial Adhesion in Bamboo Polymer Composite Enhanced with Micro-Fibrillated Cellulose","authors":"K. Okubo, T. Fujii, N. Yamashita","doi":"10.1299/JSMEA.48.199","DOIUrl":"https://doi.org/10.1299/JSMEA.48.199","url":null,"abstract":"Current study presents one of effective techniques to improve mechanical properties of PLA (Poly-Lactic Acid)-based bamboo fiber composite. Commercially available Micro-Fibrillated Cellulose (MFC) obtained from wood pulp was applied as an enhancer to the composite. The bamboo fibers were extracted by steam explosion method and they were also rubbed in water to remove xylem (soft-wall cells). The liquid-based MFC, PLA and the bamboo fiber were mixed in water for several minutes and they were filtrated under vacuum pressure. To fabricate the composite, remained sheets were then hot pressed after dry. Three-point bending strength and Mode I fracture toughness of the composite were significantly improved, even when 10% of the MFC was added into the PLA/BF composite in weight. If small amount of MFC added into the bamboo fiber composite, tangled MFC fibers prevented the growth of micro crack along the interface between bamboo fiber and matrix.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130713886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Loosening of the wheel nuts, which fix the disk wheels of automobiles to the wheel hub, may be the cause of accidents where the wheel falls off while the automobile is running. When the transverse force of wheel bolts exceeds a certain proportion of the bolt shaft force, the wheel nut begins to loosen. Further, the force on the bolt shaft may also be influenced by the loads acting to the wheel through the moment caused by the offset of the wheel. This study determined the 3-dimensional deformation of the disk wheels and the transverse forces on the wheel bolt by 3-dimensional numerical analysis. The results established that the transverse force was influenced by the bolt shaft force caused by the bolt fastening and was superposed on that due to the load, and that it fluctuated greatly during the revolution of the wheel. This phenomenon may be a large factor in the loosening of wheel nuts.
{"title":"3-Dimensional Analysis of Deformation of Disk Wheels and Transverse Force of Wheel Bolts","authors":"T. Kagiwada, H. Harada","doi":"10.1299/JSMEA.48.251","DOIUrl":"https://doi.org/10.1299/JSMEA.48.251","url":null,"abstract":"Loosening of the wheel nuts, which fix the disk wheels of automobiles to the wheel hub, may be the cause of accidents where the wheel falls off while the automobile is running. When the transverse force of wheel bolts exceeds a certain proportion of the bolt shaft force, the wheel nut begins to loosen. Further, the force on the bolt shaft may also be influenced by the loads acting to the wheel through the moment caused by the offset of the wheel. This study determined the 3-dimensional deformation of the disk wheels and the transverse forces on the wheel bolt by 3-dimensional numerical analysis. The results established that the transverse force was influenced by the bolt shaft force caused by the bolt fastening and was superposed on that due to the load, and that it fluctuated greatly during the revolution of the wheel. This phenomenon may be a large factor in the loosening of wheel nuts.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130932320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Takayuki Bessho, T. Ogasawara, T. Aoki, T. Ishikawa, Y. Ochi
The present work investigates the transient creep behavior of a plain woven Tyranno™ Lox-M (Si-Ti-C-O) fiber/SiC matrix composite at 1473K in air. Tensile creep tests were carried out under a constant load between 80 and 160MPa. A creep strain rate is generally represented by e∝ σn with a constant stress exponent, however the stress exponent decreased with time for this composite material. Monotonic tensile tests were also conducted for loading rates of 0.03, 0.3, and 3kN/min in order to investigate the effect of creep strain on tensile stress/strain behavior. Based on the empirical transient creep equation and creep-hardening model, stress/strain curves under monotonic tensile loading were predicted. A good correlation was obtained between the predicted and measured composite stress/strain curves using strain-hardening model.
{"title":"Transient Creep Behavior of a Plain Woven SiC Fiber/SiC Matrix Composite","authors":"Takayuki Bessho, T. Ogasawara, T. Aoki, T. Ishikawa, Y. Ochi","doi":"10.1299/JSMEA.48.210","DOIUrl":"https://doi.org/10.1299/JSMEA.48.210","url":null,"abstract":"The present work investigates the transient creep behavior of a plain woven Tyranno™ Lox-M (Si-Ti-C-O) fiber/SiC matrix composite at 1473K in air. Tensile creep tests were carried out under a constant load between 80 and 160MPa. A creep strain rate is generally represented by e∝ σn with a constant stress exponent, however the stress exponent decreased with time for this composite material. Monotonic tensile tests were also conducted for loading rates of 0.03, 0.3, and 3kN/min in order to investigate the effect of creep strain on tensile stress/strain behavior. Based on the empirical transient creep equation and creep-hardening model, stress/strain curves under monotonic tensile loading were predicted. A good correlation was obtained between the predicted and measured composite stress/strain curves using strain-hardening model.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133684835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jong Heon Kim, M. Niinomi, T. Akahori, Junji Takeda, H. Toda
Despite its clinical importance in developing artificial bone, limited information is available regarding the microstructure with respect to the fatigue characteristics of bones. In this study, the fatigue characteristics of the bovine humerus and femur were investigated with respect to microstructures. Fatigue tests were conducted on the bovine humerus and femur at a stress ratio of 0.1 and a frequency of 10Hz. The fatigue strength of the plexiform bone is slightly greater than that of the haversian bone. This is because the volume fraction of voids in the haversian bone, which is the site of stress concentration, is higher than that of voids in the plexiform bone. Several microcracks are observed on the fatigue fracture surface of the haversian bone. The microcracks are short and their propagation directions are random. However, the number of the microcracks in the plexiform bone is very small. The microcracks are relatively long and their propagation directions are parallel to the longitudinal direction of the lamellar bone. Therefore, the crack requires relatively more energy to propagate across the lamella in the plexiform bone.
{"title":"Effect of Microstructure on Fatigue Strength of Bovine Compact Bones","authors":"Jong Heon Kim, M. Niinomi, T. Akahori, Junji Takeda, H. Toda","doi":"10.1299/JSMEA.48.472","DOIUrl":"https://doi.org/10.1299/JSMEA.48.472","url":null,"abstract":"Despite its clinical importance in developing artificial bone, limited information is available regarding the microstructure with respect to the fatigue characteristics of bones. In this study, the fatigue characteristics of the bovine humerus and femur were investigated with respect to microstructures. Fatigue tests were conducted on the bovine humerus and femur at a stress ratio of 0.1 and a frequency of 10Hz. The fatigue strength of the plexiform bone is slightly greater than that of the haversian bone. This is because the volume fraction of voids in the haversian bone, which is the site of stress concentration, is higher than that of voids in the plexiform bone. Several microcracks are observed on the fatigue fracture surface of the haversian bone. The microcracks are short and their propagation directions are random. However, the number of the microcracks in the plexiform bone is very small. The microcracks are relatively long and their propagation directions are parallel to the longitudinal direction of the lamellar bone. Therefore, the crack requires relatively more energy to propagate across the lamella in the plexiform bone.","PeriodicalId":170519,"journal":{"name":"Jsme International Journal Series A-solid Mechanics and Material Engineering","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121154396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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